Orthodontic treatment- active components of removable orthodontic appliances bring about tooth movements
As previously discussed, removable orthodontic appliances consist of active and retentive components. The passive components are the clasps that keep the appliance secure. The active components of the appliance exert the forces that are required to engender tooth movements.
The active components consist of
- Bows- These are mainly used to fix the protrusion of the incisors. There are a variety of bows used in removable orthodontic appliances such as- short labial bow, long labial bow, split labial bow, reverse labial bow, Robert's retractor, Mills retractor, high labial bow with apron springs and fitted labial bow.
- Springs- These are used to effect specific tooth movements.
- Screws- Screws are incorporated to initiate the following movements: arch expansion, buccal movement of teeth or a tooth, or mesial or distal movements of teeth or a tooth. The base plate incorporated is generally split to embed the screw within. The screw can be turned by the patient to activate the appliance.
- Elastics- These are not commonly incorporated into removable appliances.